Cartographic editing systems typically allow users to edit read-and-write cartographic data and then save their edits. For example, the systems may allow a user to change the location of a bridge along the Rio Grande River in a cartographic representation of Alamosa County. Some systems allow the user to save the new location of the bridge by overwriting the source file. However, by overwriting the source file, the original cartographic representation in the source file is lost. Alternatively, systems may allow the user to save the new location of the bridge by saving the changes as a new revision of the cartographic representation. Yet, if the user saves the new location of the bridge as a new revision, then entire source files for the representation are duplicated and stored as new files. Multiple revisions of large source files may consume substantial amounts of memory. Furthermore, if the cartographic data is in a read-only format, then the user is not able to edit and save the edits performed on the read-only data. Accordingly, current systems of editing and storing edits to cartographic data are not very efficient.